This invention relates to an electronic control system for use with apparatus for filling flexible pouches with a product.
The use of pouches which are fabricated from a flexible material such as a suitable plastic-foil laminate is well known in the art. In particular, this technique has been employed with food products and the canning industry is fully cognizant of many problems and solutions in regard to filling a pouch or container with food in a relatively automated procedure. In regard to this, there exists many patents which show and describe the typical problems involved in processing and packaging food in flexible pouches.
Perhaps one of the most well known machines for performing such an operation is the subject matter of U.S. Pat. No. 2,649,674 issued on Aug. 25, 1953 to H. L. Bartelt entitled "PACKAGING MACHINE". This machine has been employed extensively in the packaging industry. In this machine, the pouches are formed from a strip of material and the formed pouches are advanced through various filling stations where a product is introduced into the pouches. After product introduction by one or more filling stations, the pouches are advanced to other locations where steam may be introduced in order to remove air from the pouch and to enable the product to be packaged in an oxygen free environment to enable the product to possess a relatively long shelf life. The final operation requires sealing the pouch to thereby contain the final food product. The "BARTELT" machine, as indicated, is an extremely efficient and reliable apparatus and is described in detail in the above noted patent.
Patents such as U.S. Pat. No. 4,081,942 issued on Apr. 4, 1978 and entitled "MACHINE AND METHOD FOR FILLING, INTRODUCING STEAM INTO, AND SEALING FLEXIBLE POUCHES" assigned to the Rexham Corporation of New York as well as many other patents describe various additional apparatus which is employed in conjunction with such machines to increase the efficiency and provide desired operating characteristics.
In any event, depending upon the nature of the product which is being packaged, one experiences many different types of problems. In particular, such machines have been employed for packaging sauce type food products in pouches. It is a major desire of any packaging operation to fill the pouches or containers as rapidly as possible, while further assuring that the proper quantity of food is emplaced in each pouch. In conjunction with such desired operating characteristics, is the further problem of providing a good seal for such pouches when food materials such as liquids or sauces are introduced into the flexible pouches.
As is known in the art, the nature of the retort pouch is such that the seal qualtity is critical. Top seal acceptability is affected by the presence of blemishes from occluded drops of liquid. Such blemishes can occur from splattered sauce or condensed steam. In a sauce filling operation, the droplets of sauce which may effect the seal quality can be minimized by employing a properly timed blast of air at the dispenser tip. This is referred to in the art as blow-off. The prior art techniques for introducing sauce or a liquid into a retort pouch are cognizant of the problem and do employ a blow-off operation.
In any event, it has been a continuous problem in sauce filling operations to drive the equipment at high speed in order to fill as many pouches per minute as possible, and to further assure that when operation occurs at high speed, that the blow-off is implemented at the proper time in the cycle. Essentially, if blow-off occurs too early or too late in the cycle, its effectiveness is substantially reduced.
In prior art sauce filling operations, a useful mechanism which is available has been referred to as the RAQUE filler. The Raque filler apparatus is located at a filling station location associated with a Bartelt machine. The filler employs a hopper which contains a sauce. The sauce is retracted from the hopper through a rotor valve by means of a product piston and eventually dispensed by means of a dispensing piston. The Raque filler is controlled in operation by a completely pneumatic system. Essentially, the control system uses pressurized air to perform all logic operations. Air logic has been widely employed in conjunction with packaging operations and has been extensively used with the Raque filler.
There are many disadvantages in regard to using air logic in food processing and especially where a liquid as a sauce is being dispensed. As one can imagine, impurities in the air can jam filters and mufflers associated with such systems, thus causing many failures and reductions in air pressure. Apart from these considerations is the fact that air logic operates at relatively slow speeds which are a function of the velocity of a sound pressure wave. Accordingly, the systems do not permit rapid pouch filling operations and are difficult to control in regaard to timing and operation.
By employing an electronic system, one can achieve more rapid operation and relative immunity from many problems associated with air logic. However, electronic control of such apparatus is also extremely difficult to implement due to the fact that the packing machine such as the Bartelt machine is not synchronized to the operation of the filling station and if one desires to achieve more rapid operation, one has to be assured that the entire filling sequence will occur within a predetermined interval and must occur according to the operating characteristics of the packaging machine.
In order to accomplish electronic control, the apparatus must be capable of directly inferfacing with existing packaging machines to assure reliable and optimum operation. Hence, it is a general aim of the present invention to provide a new and improved electronic control system to be used in conjunction with a pouch packaging machine and which system is adapted to control the operation of a sauce filler apparatus to provide a system capable of filling pouches with sauces or liquids at relatively high rates.
A further object of the present system is to optimumly control blow-off during a filling cycle to assure an acceptable seal quality for the pouch.